1. Field of the Invention
The present invention relates to building exhaust and ventilation systems. More particularly, the present invention relates to a system that exhausts harmful smoke, gases, or pollutants from a building in emergency and non-emergency situations.
2. Description of the Prior Art
Most fire fatalities are the result of the victim's succumbing to the deleterious effects of smoke and gas inhalation and not to the effects of the fire itself. During a fire, the airborne particles that result from combustion fill areas in the burning structure choking available air supplies and blocking escape. Many of these victims are suffocated by smoke and gas while trying to escape from a fire because such smoke and gas have displaced the breathable air in the building.
Today's advancements in material technology have exacerbated the hazards attendant with combustion byproducts and airborne particles in both the home and the work place. New building materials and their chemical combinations and combustion byproducts can produce deadly smoke and fumes, even during minor fires. Compounding this hazard is the modern practice of building air tight, energy efficient office buildings and homes that seal in harmful fumes and airborne particles during a fire or other emergency. A device that allows additional escape time during an emergency by removing airborne particles from the air supply along an escape route or area would provide a much improved survival rate for victims of fires in homes, offices, and other structures.
In the prior art, two similar ideas address the issue of maintaining air quality in a burning structure. In U.S. Pat. No. 4,765,231, A Smoke Exhausting air Conditioning System, an existing air delivery system and reverse delivery fan motors are used to evacuate smoke in an affected building. During smoke evacuation, the system controls a series of motors to direct smoke through a series of ducts. The system uses fans to push air through a supply duct. This contaminates the fresh air supply system for the building making the supply system unusable until it is cleaned. Such cleaning can be prohibitively expensive, involving replacement of duct work and other associated costs, downtime for the system and resulting loss of use of the building until the system is restored. Degraded supply system performance may also result due to residual contamination that cannot be corrected by cleaning. A detector control for such prior art system is designed to operate the system only in response to smoke and does not address the issue of hazardous fumes or other noxious pollutants. The hardware requirements for such system include an expensive central air conditioning system. Such air conditioning systems are not specifically designed to operate as a low speed pollutant exhaust. They have no provision for such function and must be significantly modified in place before such prior art can be used.
Another approach shown in the prior art is shown in U.S. Pat. No. 3,884,133, A Fire Control System For Multi-Zoned Buildings. The '133 invention is based on the principle of removing smoke from one area of a multi-zoned building while supplying air under pressure to other areas of the building, thereby slowing the spread of the fire. This operation is accomplished by controlling a complex arrangement of several ducts and fans, moving air in and out of rooms to exhaust heat and smoke, while providing positive pressure to other rooms.
The foregoing system is difficult to build, hard to reliably control and, in the event of failure could spread a fire or smoke more quickly, thereby reducing the survival rate of the structure's occupants.